Apparatus and method for transmitting and receiving data in a communication system

ABSTRACT

An apparatus and method for transmitting and receiving data in a communication system are provided. In the method, a BS selects a repeater group from among a plurality of repeater groups, for use in transmitting first data to an MS and transmits the first data to the MS according to the number of repeaters of the selected repeater group. The first data is different from data transmitted by the repeaters of the selected repeater group.

PRIORITY

This application claims the benefit under 35 U.S.C. §119(a) of a Koreanpatent application filed in the Korean Intellectual Property Office onOct. 30, 2007 and assigned Serial No. 10-2007-0109744, the entiredisclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to data transmission and reception in acommunication system. More particularly, the present invention relatesto an apparatus and method for transmitting and receiving data in acommunication system using repeaters.

2. Description of the Related Art

In a communication system, a Base Station (BS) transmits and receivesdata to and from a Mobile Station (MS) via a direct link. Due to thefixedness of the BS, a shadowing area may exist within the coverage areaof the BS or channel status may fluctuate. Therefore, the communicationsystem has limitations in efficiently providing a communication service.To avert this problem, the communication system employs repeaters foramplification and coverage expansion of signals from the BS.

The use of repeaters expands a cell coverage area and provides a betterchannel to an MS. In addition, the BS can provide a high-speed datachannel to an MS at a cell boundary that worsens the channel status viathe repeater.

In the communication system, the BS can use repeaters for datatransmission and reception to and from the MS. With reference to FIG. 1,the structure of frames transmitted from a BS and repeaters will bedescribed below.

FIG. 1 illustrates a frame structure for data transmission and receptionof a BS and repeaters in a conventional communication system.

The communication system comprises a BS, an MS, and repeaters forrelaying signals between the BS and the MS.

Referring to FIG. 1, when the BS transmits and receives data to and fromthe MS, each frame transmitted from the BS and the repeaters, Repeater 1to Repeater n comprises DownLink (DL) and UpLink (UL) areas.

The DL area comprises a preamble, a MAP, and data bursts. The preambledelivers a synchronization signal for synchronization acquisition. TheMAP comprises data restoration information for restoring the data of thedata bursts. The data bursts carry the transmission data.

The frames transmitted from the BS and the repeaters are configured totransmit the same data simultaneously. In this context, there exists aneed for developing a technique for increasing overall system capacitythrough efficient use of resources in a system having a BS andrepeaters.

SUMMARY OF THE INVENTION

An aspect of the present invention is to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentinvention is to provide an apparatus and method for transmitting andreceiving data in a communication system.

Another aspect of the present invention is to provide an apparatus andmethod for transmitting and receiving data in a communication systemusing repeaters.

A further aspect of the present invention is to provide an apparatus andmethod for transmitting and receiving data to increase system capacityin a communication system using repeaters.

Still another aspect of the present invention is to provide an apparatusand method for transmitting and receiving data to reduce interferencebetween repeaters during data transmission and reception in acommunication system using repeaters.

In accordance with an aspect of the present invention, a method fortransmitting data in a BS in a communication system is provided. In themethod, a repeater group is selected from among a plurality of repeatergroups, for use in transmitting first data to an MS and the first datais transmitted to the MS according to the number of repeaters of theselected repeater group. The first data is different from datatransmitted by the repeaters of the selected repeater group.

In accordance with another aspect of the present invention, a method forreceiving data in an MS in a communication system is provided. In themethod, first data transmitted by a BS is received from repeaters of arepeater group. The repeater group is selected from among a plurality ofrepeater groups, for transmission of the first data by the BS, the firstdata is received according to the number of the repeaters of theselected repeater group, and the first data received from the repeatersof the selected repeater group is different according to the repeatersof the selected repeater group.

In accordance with a further aspect of the present invention, anapparatus for transmitting data in a communication system is provided.The apparatus comprises a BS that selects a repeater group from among aplurality of repeater groups, for use in transmitting first data to anMS, and transmits the first data to the MS according to the number ofrepeaters of the selected repeater group. The first data is differentfrom data transmitted by the repeaters of the selected repeater group.

In accordance with still another aspect of the present invention, anapparatus for receiving data in a communication system is provided. Theapparatus comprises an MS that receives first data transmitted by a BSfrom repeaters of a repeater group. The repeater group is selected fromamong a plurality of repeater groups, for transmission of the first databy the BS, the first data is received according to the number of therepeaters of the selected repeater group, and the first data receivedfrom the repeaters of the selected repeater group is different accordingto the repeaters of the selected repeater group.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certainexemplary embodiments of the present invention will be more apparentfrom the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a frame structure for data transmission and receptionof a BS and repeaters in a conventional communication system;

FIG. 2 illustrates a configuration of a communication system accordingto an exemplary embodiment of the present invention;

FIG. 3A illustrates a Time Division Multiplexing (TDM) frame structurein a communication system according to an exemplary embodiment of thepresent invention;

FIG. 3B illustrates a Frequency Division Multiplexing (FDM) framestructure in a communication system according to an exemplary embodimentof the present invention;

FIG. 4 is a block diagram of a macro Base Station (BS) in acommunication system according to an exemplary embodiment of the presentinvention;

FIG. 5 is a flowchart illustrating an operation of a BS for selectingmicro-zone repeaters to communicate with a Mobile Station (MS) in acommunication system according to an exemplary embodiment of the presentinvention;

FIG. 6 is a flowchart illustrating an operation of a BS for selectingmicro-zone repeaters to communicate with an MS in a communication systemaccording to an exemplary embodiment of the present invention;

FIG. 7A illustrates a micro-zone repeater group that is involved in datatransmission from a BS to an MS in a k^(th) frame in a communicationsystem according to an exemplary embodiment of the present invention;

FIG. 7B illustrates a micro-zone repeater group that is involved in datatransmission from a BS to an MS in a (k+1)^(th) frame in a communicationsystem according to an exemplary embodiment of the present invention;

FIG. 8 is a flowchart illustrating an operation of a MS for selectingmicro-zone repeaters according to an exemplary embodiment of the presentinvention;

FIG. 9 is a flowchart illustrating an operation of a MS for selectingmicro-zone repeaters according to an exemplary embodiment of the presentinvention;

FIG. 10 is a flowchart illustrating an operation of a BS for selectingmicro-zone repeaters according to an exemplary embodiment of the presentinvention; and

FIG. 11 is a flowchart illustrating an operation of a BS for schedulingavailable micro-zone repeater groups according to an exemplaryembodiment of the present invention.

Throughout the drawings, the same drawing reference numerals will beunderstood to refer to the same elements, features and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It comprises various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the exemplary embodiments describedherein can be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions are omitted for clarity and conciseness.

Exemplary embodiments of the present invention provide an apparatus andmethod for transmitting and receiving data in a communication system,for example, a communication system using repeaters. In accordance withexemplary embodiments of the present invention, a BS and at least onerepeater connected to the BS transmit data in separate zones of a framedepending on whether the data is the same or different in thecommunication system. While the following description is made in thecontext of a repeater that relays a signal from the BS, for the sake ofconvenience, it is to be understood that the present invention is alsoapplicable to other devices and methods for relaying signals from a BS.For the sake of convenience, a BS and a repeater are referred to as amacro BS and a micro-zone repeater, respectively.

In the following description of exemplary embodiments of the presentinvention, the term “macro zone: refer to an area in which a macro BSand micro-zone repeaters can transmit the same data simultaneously andthe term “micro zone” refer to an area in which the macro BS and themicro-zone repeaters can transmit the same or different datasimultaneously.

A micro zone may comprise an area in which the macro BS and a micro-zonerepeaters can transmit data to a particular MS in cooperation.Therefore, the macro BS and the micro-zone repeaters can transmit thesame or different data to the MS in cooperation.

The micro zone is divided into at least two areas. In a first area, themacro BS and the micro-zone repeaters transmit different data. In thesecond area, the macro BS and the micro-zone repeaters transmit the samedata.

In an exemplary embodiment, a transmission frame can be divided into azone in which the macro BS and the micro-zone repeaters transmitdifferent data and a zone in which they transmit the same data incooperation.

For example, if the sizes of the macro zone and the micro zone areflexible, the Carrier-to-Interference and Noise Ratios (CINRs) of everyMS is measured in the macro zone and the micro zone and ProportionalFairness (PF) metrics for the macro zone and the micro zone arecalculated for the MS. Then MSs are allocated to the macro zone or themicro zone in a descending order of PF metrics. In this manner, usersare automatically selected for the macro zone and the micro zone. On theother hand, if the macro zone and the micro zone are of fixed sizes,users are selected on a zone basis.

FIG. 2 illustrates a configuration of a communication system accordingto an exemplary embodiment of the present invention.

Referring to FIG. 2, the communication system comprises a macro BS 200and a plurality of (first to fifth) micro-zone repeaters 210, 220, 230,240 and 250 connected to the macro BS 200. The macro BS 200 covers amacro cell 201 and the first to fifth micro-zone repeaters 210, 220,230, 240 and 250 cover first to fifth micro cells 211, 221, 231, 241 and251, respectively.

The macro BS 200 and the micro-zone repeaters 210, 220, 230, 240 and 250each can use a single antenna or multiple antennas. In addition, themacro BS 200 and the micro-zone repeaters 210, 220, 230, 240 and 250 canoperate in at least one of Time Division Multiplexing (TDM) andFrequency Division Multiplexing (FDM).

The macro BS 200 divides a frame into a macro zone in which the macro BS200 and the micro-zone repeaters 210, 220, 230, 240 and 250 transmit thesame data and a micro zone in which they transmit different data. Themacro zone and the micro zone are determined by the macro BS 200depending on system situations or setting, for example. Once MSs areselected for data communication, the macro zone and the micro zone canbe automatically determined according to an exemplary embodiment of thepresent invention.

The macro BS 200 controls such that the macro BS 200 and the micro-zonerepeaters 210, 220, 230, 240 and 250 transmit data discriminately ineach frame.

Now frame structures for data transmission from the macro BS and themicro-zone repeaters will be described with reference to FIGS. 3A and3B.

FIG. 3A illustrates a TDM frame structure in a communication systemaccording to an exemplary embodiment of the present invention.

Referring to FIG. 3A, the frame structure is for frames transmitted fromthe macro BS and the micro-zone repeaters. Each of the frames comprisesa DownLink (DL) area and an UpLink (UL) area. The DL area comprises amacro zone and a micro zone. The macro zone comprises a preamble, a MAP,and data bursts and the micro zone delivers data bursts.

Since the macro BS and the micro-zone repeaters use TDM frames, the databurst area of the macro zone is distinguished from that of the microzone in time.

Hence, in the macro zone, the macro BS and the micro-zone repeaterstransmit the same first to fourth data bursts. Meanwhile, in the microzone, the macro BS transmits fifth to eighth data bursts, a firstmicro-zone repeater transmits ninth to twelfth data bursts, and ann^(th) micro-zone repeater transmits (k−3)^(th) to k^(th) data bursts.

FIG. 3B illustrates an FDM frame structure in a communication systemaccording to an exemplary embodiment of the present invention.

Referring to FIG. 3B, the frame structure is for frames transmitted fromthe macro BS and the micro-zone repeaters. Each of the frames comprisesa DL area and a UL area. The DL area comprises a macro zone and a microzone. The macro zone comprises a preamble, a MAP, and data bursts andthe micro zone delivers data bursts.

Since the macro BS and the micro-zone repeaters use FDM frames, the databurst area of the macro zone is distinguished from that of the microzone in frequency.

Hence, in the macro zone, the macro BS and the micro-zone repeaterstransmit the same first to fourth data bursts. Meanwhile, in the microzone, the macro BS transmits fifth to eighth data bursts, a firstmicro-zone repeater transmits ninth to twelfth data bursts, and ann^(th) micro-zone repeater transmits (k−3)^(th) to k^(th) data bursts.

A description will be made of the configuration of a BS for generating aframe divided into a macro zone and a micro zone with reference to FIG.4.

FIG. 4 is a block diagram of a macro BS in a communication systemaccording to an exemplary embodiment of the present invention.

Referring to FIG. 4, the communication system comprises a macro BS 400and first to n^(th) micro-zone repeaters 430 to 460. The macro BS 400can be connected to the first to n^(th) micro-zone repeaters 430 to 460wirelessly or by cable. In the illustrated case of FIG. 4, the macro BS400 is connected to the first to n^(th) micro-zone repeaters 430 to 460by cable.

The macro BS 400 comprises a data buffer 411, a data processor 413, amacro zone/micro zone data divider 415, and a micro zone data divider417.

The data buffer 411 buffers data to be transmitted to an MS.

The data processor 413 processes the buffered transmission data. Forexample, the data processing comprises encoding and modulation.

The macro zone/micro zone data divider 415 divides the processed datainto data for a macro zone and data for a micro zone in a frame. Themacro zone/micro zone data divider 415 transmits the macro-zone data toan antenna of the macro BS 400 and the first to n repeaters 430 to 460,respectively. Also, the macro zone/micro zone data divider 415 providesthe micro-zone data to the micro zone data divider 417.

The micro zone data divider 417 divides the received micro-zone datainto micro-zone data for the macro BS 400 and respective micro-zone datafor the first to n^(th) micro-zone repeater 430 to 460 and transmits thedivided micro-zone data to the antenna of the macro BS 400 and the firstto n^(th) repeaters 430 to 460, respectively.

For transmission of the micro-zone data the first to n^(th) repeaters430 to 460, the micro zone data divider 417 can use dedicated radiolinks or fiber/optic lines free of mutual interference among the antennaof the macro BS 400 and the antennas of the first to n^(th) repeaters430 to 460.

The macro BS 400 generates data frames for the macro BS 400 itself andfor the first to n^(th) repeaters 430 to 460. It can also determine thestart positions of the micro zones of the frames, taking into accountthe sizes of transmission data.

While not shown, the macro BS has an apparatus for detecting,demodulating, and decoding data received through the macro-BS antennaand data received from the first to n^(th) repeaters 430 to 460.

The macro BS may further comprise an apparatus for controlling thetransmit power of the first to n^(th) repeaters 430 to 460 to controlinterference among the micro-zone repeaters 430 to 460 and increasetheir reception rates. For instance, the macro BS 400 can controlinterference and increase the data reception rate of an MS by allocatinghigh transmit power levels to micro-zone repeaters transmitting data andmicro-zone repeaters far apart from other ones.

To communicate with the macro BS, the MS performs initial network entryto the macro BS. Upon turning on, the MS measures the signal strengthsof adjacent macro BSs and selects the macro BS having the highest signalstrength as its serving macro BS.

Alternatively, upon turning on, the MS measures the signal strengths ofadjacent micro-zone repeaters and selects micro-zone repeaters havingsignal strengths higher than a predefined threshold. Then the MSgenerates a list of the selected micro-zone repeaters and selects amacro BS connected to most of the listed micro-zone repeaters as itsserving macro BS.

The MS notifies the selected macro BS that it is the serving macro BSand carries out data transmission and reception with the serving macroBS.

The macro BS may determine whether to communicate with the MS directlyor through micro-zone repeaters communicating with the macro BS. Inother words, the macro BS selects the macro-BS antenna or micro-zonerepeater antennas, for communication with the MS.

To transmit data in the micro zone, the macro BS selects micro-zonerepeaters. With reference to FIGS. 5 and 6, an operation of the macro BSfor selecting micro-zone repeaters to communicate with the macro BS inorder to transmit and receive data to and from an MS will be describedbelow.

FIG. 5 is a flowchart illustrating an operation of a BS for selectingmicro-zone repeaters to communicate with an MS in a communication systemaccording to an exemplary embodiment of the present invention.

Referring to FIG. 5, the macro BS completes an initial connection forcommunications with the MS (MS i) in step 511.

The macro BS measures the Received Signal Strengths (RSSs) of MS i instep 513. More specifically, the macro BS measures the RSSs of MS i atthe antennas of micro-zone repeater communicating with the macro BS.Assuming that the index of a micro zone-repeater is denoted by j, thenthe RSSs can be represented as RSSij. While the description is made inthe context of RSS, the RSS can be replaced by CINR.

In step 515, the macro BS selects a group of micro-zone repeaters jhaving RSSs equal to or larger than a predefined threshold.

The macro BS compares the number of the micro-zone repeaters in theselected group with 0 (Num of Group==0) in step 517.

If the number of the micro-zone repeaters in the selected group is 0,the macro BS transmits and receives data to and from MS i directly instep 519. Herein, the macro BS can use micro-zone repeaters adjacent tothe MS as well, for data transmission and reception to and from the MS.For example, one or more micro-zone repeaters transmit the same ordifferent data to the MS in the micro zones of their frames. In theformer case, they can adopt beamforming and in the latter case, they canoperate in Multiple Input Multiple Output (MIMO).

On the contrary, if the number of the micro-zone repeaters in theselected group is not 0 in step 517, the macro BS compares the number ofthe micro-zone repeaters with 1 (Num of Group==1) in step 521.

If the selected group comprises a single micro-zone repeater, the macroBS transmits and receives data to and from the MS via the micro-zonerepeater j of the selected group in step 523.

If the number of the micro-zone repeaters in the selected group is not1, the macro BS determines whether the selected group comprises two ormore micro-zone repeaters (Num of Group>1) in step 525.

If the selected group comprises two or more micro-zone repeaters, themacro BS transmits and receives data to and from the MS via themicro-zone repeaters of the selected group, for example, micro-zonerepeater 1 to micro-zone repeater N in step 527. That is, the datatransmission and reception is done via all micro-zone repeaters of theselected group.

If the number of the micro-zone repeaters in the selected group does notexceed 1 in step 525, the macro BS ends the procedure.

In FIG. 5, the macro BS can transmit and receive data to and from the MSwithout signaling for selection of micro-zone repeaters. Also, the macroBS can communicate with the MS even though the MS cannot identify theselected micro-zone repeaters.

FIG. 6 is a flowchart illustrating an operation of a BS for selectingmicro-zone repeaters to communicate with an MS in a communication systemaccording to an exemplary embodiment of the present invention.

Referring to FIG. 6, the macro BS completes an initial connection forcommunications with the MS (MS i) in step 611.

The macro BS receives micro-zone repeater group information and ChannelQuality Information (CQI) measured with respect to the macro BS from MSi in step 613.

To be more specific, MS i measures the RSSs of micro-zone repeaters andselects micro-zone repeaters having RSSs larger than a predefinedthreshold. MS i groups the selected micro-zone repeaters and transmitsinformation about the micro-zone repeater group to the macro BS.

The CQI is measured about each micro-zone repeater of the micro-zonerepeater group. A BS scheduler can use the CQI to maximize capacity oracquire PF metrics.

In step 615, the macro BS compares the number of the micro-zonerepeaters in the selected group with 0 (Num of Group==0).

If the number of the micro-zone repeaters in the selected group is 0,the macro BS transmits and receives data to and from MS i directly instep 617. Herein, the macro BS can use micro-zone repeaters adjacent tothe MS as well, for data transmission and reception to and from the MS.For example, one or more micro-zone repeaters transmit the same ordifferent data to the MS in the micro zones of their frames. In theformer case, they can adopt beamforming and in the latter case, they canoperate in MIMO.

In contrast, if the number of the micro-zone repeaters in the selectedgroup is not 0 in step 615, the macro BS compares the number of themicro-zone repeaters with 1 (Num of Group==1) in step 619.

If the selected group comprises a single micro-zone repeater, the macroBS transmits and receives data to and from the MS via the micro-zonerepeater j of the selected group in step 621.

If the number of the micro-zone repeaters in the selected group is not 1in step 619, the macro BS determines whether the selected groupcomprises two or more micro-zone repeaters (Num of Group>1) in step 623.

If the selected group comprises two or more micro-zone repeaters, themacro BS transmits and receives data to and from the MS via themicro-zone repeaters of the selected group, for example, micro-zonerepeater 1 to micro-zone repeater N in step 625. That is, the datatransmission and reception is done via all micro-zone repeaters of theselected group.

If the number of the micro-zone repeaters in the selected group does notexceed 1 in step 623, the macro BS ends the procedure.

In FIG. 6, when the macro BS selects micro-zone repeaters to communicatewith the MS, consumption of unnecessary UL resources can be prevented.

In FIGS. 5 and 6, the macro BS is responsible for selecting micro-zonerepeaters to communicate with the MS.

The data transmission/reception schemes illustrated in FIGS. 5 and 6 canapply to DL/UL data transmission/reception between the macro BS and theMS. For example, the UL data transmission/reception may be performed inthe data transmission/reception scheme of FIG. 5 and the DL datatransmission/reception may be performed in the datatransmission/reception scheme of FIG. 6, or vice versa.

The micro-zone repeater group for use in data transmission/receptionbetween the macro BS and the MS will be described below with referenceto FIGS. 7A and 7B.

FIG. 7A illustrates a micro-zone repeater group that is involved in datatransmission from a BS to a MS in a k^(th) frame in a communicationsystem according to an exemplary embodiment of the present invention.

Referring to FIG. 7A, the BS has selected the micro-zone repeater groupfor data transmission to the MS. In the illustrated case of FIG. 7A, themacro BS transmits data to the MS in the macro zone and the micro zoneof a k^(th) frame.

The k^(th) frame comprises a preamble, a MAP and data bursts in themacro zone. In the macro zone, the macro BS and each micro-zone repeatertransmit the same data.

In the micro zone, first, third and fifth micro-zone repeaters of themicro-zone repeater group selected by the macro BS transmit data to theMS. According to an exemplary embodiment of the present invention, themicro-zone repeaters are isolated from one another, that is, there is nointerference among them during data transmission in the micro zone.

FIG. 7B illustrates a micro-zone repeater group that is involved in datatransmission from a BS to a MS in a (k+1)^(th) frame in a communicationsystem according to an exemplary embodiment of the present invention.

Referring to FIG. 7B, the BS has selected the micro-zone repeater groupsfor data transmission to the MS. In the illustrated case of FIG. 7B, themacro BS transmits data to the MS in the macro zone and the micro zoneof a (k+1)^(th) frame.

The (k+1)^(th) frame comprises a preamble, a MAP and data bursts in themacro zone. In the macro zone, the macro BS and each micro-zone repeatertransmit the same data.

In the micro zone, second, third and fourth micro-zone repeaters of themicro-zone repeater group selected by the macro BS transmit data to theMS. According to an exemplary embodiment of the present invention, themicro-zone repeaters are isolated from one another, that is, there is nointerference among them during data transmission in the micro zone.

In FIGS. 7A and 7B, the micro-zone repeaters transmit data in the microzone, isolated from one another. That is, only micro-zone repeaters thatminimize mutual interference are selected for data transmission in themicro zone.

The other micro-zone repeaters excluded from the micro-zone repeatergroup transmit null data or do not transmit any data in accordance withan exemplary embodiment of the present invention.

As described above, when all repeaters transmit the same data in acommunication system using repeaters, an increase in the number ofrepeaters leads to increased CINRs, which in turn increases systemcapacity. Meanwhile, if micro-zone repeaters are used, they can transmitdifferent data. Even in this case, CINRs can be increased and datacapacity can be maximized with additional use of resources.

In the communication system using micro-zone repeaters, spatialresources can be increased by using more micro-zone repeaters. However,low isolation among micro-zone repeaters decreases CINRs due tointerference from other micro-zone repeaters. As a consequence, systemcapacity can be decreased.

Accordingly, an exemplary embodiment of the present invention generatesmicro-zone repeater groups with isolated micro-zone repeater antennasand transmits data via micro-zone repeaters scheduled for a currentframe or band. In addition, an exemplary embodiment of the presentinvention selects micro-zone repeater groups by use of a predefinedmetric and schedules the micro-zone repeater groups.

With reference to FIGS. 8 and 9, operations of the macro BS and the MSfor selecting a micro-zone repeater group will be described below.

FIG. 8 is a flowchart illustrating an operation of a MS for selectingmicro-zone repeaters according to an exemplary embodiment of the presentinvention.

Referring to FIG. 8, the MS measures the reception signal power levelsPr of micro-zone repeaters in step 811.

In step 813, the MS generates a list of micro-zone repeaters withreception signal power levels Pr larger than a predefined threshold Pth(Pr>Pth).

The MS measures the CINRs of every micro-zone repeater combination kthat can be produced from the micro-zone repeater list in step 815. TheCINRs can be expressed as CINR_(j,k) where j denotes the index of the MSand k denotes the micro-zone repeater combination. The micro-zonerepeater combination k may comprise one or more micro-zone repeaters.

In step 817, the MS transmits the micro-zone repeater list andCINR_(j,k) to its serving macro BS. The micro-zone repeater list andCINR_(j,k) can be transmitted to the serving macro BS in the micro zone.

FIG. 9 is a flowchart illustrating an operation of a MS for selectingmicro-zone repeaters according to an exemplary embodiment of the presentinvention.

Referring to FIG. 9, the MS generates a list of all micro-zone repeaterswithin the coverage area of its serving macro BS in step 911.

The MS measures the CINRs of every possible micro-zone repeatercombination m that can be produced from the micro-zone repeater list instep 913. The CINRs can be expressed as CINR_(j,m) where j denotes theindex of the MS and m denotes the micro-zone repeater combination.

For example, on the assumption that the micro-zone repeater listcomprises three micro zone-repeaters A, B and C and micro-zone repeaterA is a serving micro-zone repeater, the micro-zone repeater combinationsthat can be produced using the micro-zone repeater list can be createdas illustrated in Table 1.

TABLE 1 Case Repeater A Repeater B Repeater C 1 ◯ ◯ ◯ 2 ◯ ◯ * 3 ◯ * ◯ 4◯ * * 5 ◯ ◯ X 6 ◯ X ◯ 7 ◯ X X

In Table 1, O indicates that the micro-zone repeater transmits data toMS j, * indicates that the micro-zone repeater transmits data to anotherMS, and X indicates that the micro-zone repeater does not transmit data.

The MS measures the CINRs of each case listed in Table 1, CINR_(j,m).

In step 915, the MS transmits the micro-zone repeater list andCINR_(j,m) to its serving macro BS. The micro-zone repeater list andCINR_(j,k) can be transmitted to the serving macro BS in the micro zone.

While FIGS. 8 and 9 have been described in the context of CINR by way ofexample, the CINR can be replaced with any one or combination of otherCQI, for example, Signal-to-Noise Ratio (SNR), Signal-to-Interferenceand Noise Ratio (SINR), or Carrier-to-Interference Ratio (CIR). Inaddition, the DL/UL RSS of the MS can substitute for the CINR.

In addition, while it has been described in the exemplary embodiments ofthe present invention that the MS transmits a micro-zone repeater listto the macro BS, it can be further contemplated that instead of themicro-zone repeater list, the MS transmits a list of micro-zone repeatercombinations produced using the micro-zone repeater list.

FIG. 10 is a flowchart illustrating an operation of a macro BS forselecting micro-zone repeaters according to an exemplary embodiment ofthe present invention.

Referring to FIG. 10, the macro BS receives a micro-zone repeater listand CINRs in step 1011. The CINRs can be CINR_(j,k) or CINR_(j,m).

In step 1013, the macro BS generates cases (case i) for each super-set.

The super-set refers to a set of micro-zone repeater combinations withhigh isolation levels selected from among the micro-zone repeatercombinations that are produced using the micro-zone repeater list. Themacro BS creates cases using the micro-zone repeaters of the super-set.When creating cases, the macro BS limits the number of micro-zonerepeaters in a micro-zone repeater combination that can transmit andreceive data simultaneously with the macro BS within the capacity of itsmodem.

In step 1015, the macro BS calculates the capacity of each case by

$\begin{matrix}{C_{s,i} = {\alpha_{i}{\sum\limits_{j}{{\log \left( {1 + {CINR}_{j,k}} \right)} \cdot \frac{1}{O_{j,k}}}}}} & (1)\end{matrix}$

where C_(s,i) denotes the capacity of case i in the superset, α_(i)denotes a weight for case i, CINR_(j,k) denotes the CINRs received fromMS j, and O_(j,k) denotes the number of overlays for CINR_(j,k), i.e.the number of micro-zone repeaters comprised in a micro-zone repeatergroup.

In step 1017, the macro BS arranges the capacities C_(s,i) in adescending order.

The macro BS selects a case with the largest capacity, excludes casesthat each comprise at least one micro-zone repeater comprised in theselected case, selects a case with the largest capacity from among theremaining cases, and updates the number of selected cases S_(i) forsuperset i (S_(i)=S_(i)+1) in step 1019.

In step 1021, the macro BS compares the number of selected cases S_(i)with a minimum frame number f. If S_(i) is larger than f, Quality ofService (QoS) cannot be guaranteed for each MS. Therefore, even throughS_(i) is equal to f(S_(i)= f), when there is an unselected micro-zonerepeater, a case including the unselected micro-zone repeater isselected so that every micro-zone repeater can be comprised in cases.

If S_(i) is equal to or less than f, the macro BS goes to step 1023. IfS_(i) is larger than f, the macro BS goes to step 1025.

In step 1025, the macro BS selects a case including a currentlyunselected micro-zone repeater and at least one micro-zone repeater ofthe last case in superset i. Thereafter, the macro BS ends theprocedure.

In step 1023, the macro BS determines whether every micro-zone repeaterhas been selected.

If every micro-zone repeater has been selected, the macro BS ends theprocedure. If there is still an unselected micro-zone repeater, themacro BS returns to step 1019.

Now a method for scheduling available micro-zone repeater groups in themacro BS will be described with reference to FIG. 11.

FIG. 11 is a flowchart illustrating an operation of a BS for schedulingavailable micro-zone repeater groups according to an exemplaryembodiment of the present invention.

Referring to FIG. 11, the macro BS selects a micro-zone repeater groupG_(n,m) having the highest weight in step 1111. If an m^(th) selectedcase in superset n is referred to as case m, case m, i.e. the micro-zonerepeater group corresponding to case m is denoted by G_(n,m). The weightof the micro-zone repeater group G_(n,m) is determined according to itsQoS and system capacity.

The macro BS calculates its required processing capability A_(sum) toprocess the selected micro-zone repeater group in step 1113. When therequired processing capability of the macro BS for the selectedmicro-zone repeater group is denoted by A_(m,n), A_(sum)=A_(m,n). Therequired processing capability can be the number of micro-zone repeaterantennas or the number of MSs that can be processed in the macro BS.Herein, the required processing capability is the number of micro-zonerepeater antennas that can be processed in the macro BS.

In step 1115, the macro BS compares the required processing capabilityA_(sum) with its maximum processing capability A_(MAX)(A_(sum)==A_(MAX)). If the required processing capability satisfies themaximum processing capability, the macro BS goes to step 1125 andotherwise, it goes to step 1117.

If A_(sum)>A_(MAX), the macro BS excludes the last selected micro-zonerepeater group and re-calculates the resulting required processingcapability (A_(sum)=A_(sum)−A_(last) where A_(last) denotes a processingcapability required for the last selected micro-zone repeater group) instep 1117. The macro BS repeats the selection of a micro-zone repeatergroup, taking into account the capability of the modem as well as thehighest weight. The above operation is for excluding the last selectedmicro-zone repeater group.

In step 1119, the macro BS determines whether there is a micro-zonerepeater group with antennas, the number of which, satisfies(A_(MAX)−A_(sum)) in an unselected superset.

In the absence of the micro-zone repeater group, the macro BS proceedsto step 1125. On the other hand, in the presence of the micro-zonerepeater group, the macro BS proceeds to step 1121.

The macro BS selects a micro-zone repeater group G_(i,j) having thehighest weight in step 1121 and adds the processing capability A_(i,j)required for G_(i,j) to A_(sum) (A_(sum)=A_(sum)+A_(i,j)) in step 1123.Then the macro BS returns to step 1117.

In step 1125, the macro BS updates the weight of the selected micro-zonerepeater group G_(i,j), i.e. W_(i,j)=f(W_(i,j)) for all i,j.

While one frame is divided into a macro zone and a micro zone inexemplary embodiments of the present invention, it can be furthercontemplated that the macro zone and the micro zone can be defined onthe basis of a plurality of frames.

As is apparent from the above description, exemplary embodiments of thepresent invention advantageously increases the system capacity of acommunication system using repeaters. Especially as a frame is dividedinto two zones for data transmission and data is scheduled for eachzone, exemplary embodiments of the present invention can controlinterference between repeaters during data transmission and reception.

While the invention has been shown and described with reference tocertain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the presentinvention as defined by the appended claims and their equivalents.

1. A method for transmitting data in a Base Station (BS) in acommunication system, the method comprising: selecting a repeater groupfrom among a plurality of repeater groups, for use in transmitting firstdata to a Mobile Station (MS); and transmitting the first data to the MSaccording to the number of repeaters of the selected repeater group,wherein the first data is different from data transmitted by therepeaters of the selected repeater group.
 2. The method of claim 1,wherein the transmitting of the first data comprises: transmittinginformation about a start position of a first zone of a frame to therepeaters of the selected repeater group; and transmitting second datain a second zone of the frame and the first data in the first zone ofthe frame, wherein the second data is identical to and simultaneous withdata transmitted by the repeaters of the selected repeater group and thedata transmitted by each of the repeaters of the selected repeater groupis transmitted from the start position of the first zone of the frame ineach of the repeaters of the selected repeater group.
 3. The method ofclaim 2, further comprising transmitting third data to the MS in thefirst zone of the frame in cooperation with the repeaters of theselected repeater group.
 4. The method of claim 1, wherein thetransmitting of the first data comprises: counting the number of therepeaters of the selected repeater group; transmitting the first datadirectly to the MS when the number of the repeaters of the selectedrepeater group is 0; transmitting the first data to the MS via thesingle repeater of the selected repeater group when the number of therepeaters of the selected repeater group is 1; and transmitting thefirst data to the MS via all repeaters of the selected repeater groupwhen the number of the repeaters of the selected repeater group is 2 orlarger.
 5. The method of claim 1, wherein the selecting of the repeatergroup comprises selecting a repeater group based on repeater groupinformation and Channel Quality Information (CQI) about channelqualities between the MS and repeaters connected to the MS, the repeatergroup information and the CQI being received from the MS.
 6. The methodof claim 1, wherein the selecting of the repeater group comprisesselecting a repeater group including repeaters with signal strengthsmeasured by the MS larger than a threshold from among the plurality ofrepeater groups.
 7. The method of claim 1, wherein the selecting of therepeater group comprises selecting a repeater group including repeaterswith minimal mutual interference from among the plurality of repeatergroups.
 8. The method of claim 1, wherein the selecting of the repeatergroup comprises: receiving a repeater list comprising repeaters within acoverage area of the BS and Channel Quality Information (CQI) of therepeaters within the coverage area of the BS from the MS; calculating acapacity of each repeater group using the repeater list; and selecting arepeater group with a largest capacity.
 9. A method for receiving datain a Mobile Station (MS) in a communication system, the methodcomprising: receiving first data transmitted by a Base Station (BS) fromrepeaters of a repeater group, wherein the repeater group is selectedfrom among a plurality of repeater groups, for transmission of the firstdata by the BS, the first data is received according to the number ofthe repeaters of the selected repeater group, and the first datareceived from the repeaters of the selected repeater group is differentaccording to the repeaters of the selected repeater group.
 10. Themethod of claim 9, wherein the receiving of the first data comprises:transmitting repeater group selecting information to the BS, for use inselecting the repeater group for transmission of the first data fromamong the plurality of repeater groups; and receiving the first datafrom the repeaters of the repeater group after the repeater groupselecting information is transmitted.
 11. The method of claim 10,wherein the transmitting of the repeater group information comprises:measuring received signal power of at least one repeater; generating arepeater list including repeaters having received signal powers largerthan a threshold; measuring Channel Quality Information (CQI) about eachrepeater combination that can be produced using the repeater list; andtransmitting the repeater list and the CQI to the BS.
 12. The method ofclaim 11, wherein the CQI is at least one of Carrier-to-Interference andNoise Ratio (CINR), Signal-to-Noise Ratio (SNR), Signal-to-Interferenceand Noise Ratio (SINR), Carrier-to-Interference Ratio (CIR), andReceived Signal Strength (RSS).
 13. The method of claim 9, wherein thereceiving of the first data comprises: receiving information about astart position of a first zone of a frame from the BS; and receivingsecond data in a second zone of the frame and the first data in thefirst zone of the frame, starting from the start position of the firstzone indicated by the received information, wherein the second data isidentical to and simultaneous with data transmitted by the repeaters ofthe selected repeater group and the first data is received from therepeaters of the selected repeater group, starting from the startposition of the first zone of the frame.
 14. The method of claim 9,further comprising receiving third data in the first zone of the frametransmitted by the BS in cooperation with the repeaters of the selectedrepeater group.
 15. The method of claim 9, wherein the transmitting ofthe repeater group information comprises: generating a repeater listusing all repeaters within a coverage area of the BS; generatingrepeater combinations using the repeater list; measuring Channel QualityInformation (CQI) about each of the repeater combinations; andtransmitting the repeater list and the CQI to the BS.
 16. The method ofclaim 15, wherein the CQI is at least one of Carrier-to-Interference andNoise Ratio (CINR), Signal-to-Noise Ratio (SNR), Signal-to-Interferenceand Noise Ratio (SINR), Carrier-to-Interference Ratio (CIR), andReceived Signal Strength (RSS).
 17. An apparatus for transmitting datain a communication system, the apparatus comprising: a Base Station (BS)for selecting a repeater group from among a plurality of repeatergroups, for use in transmitting first data to a Mobile Station (MS), andfor transmitting the first data to the MS according to the number ofrepeaters of the selected repeater group, wherein the first data isdifferent from data transmitted by the repeaters of the selectedrepeater group.
 18. The apparatus of claim 17, wherein the BS transmitsinformation about a start position of a first zone of a frame to therepeaters of the selected repeater group, and transmits second data in asecond zone of the frame and the first data in the first zone of theframe, wherein the second data is identical to and simultaneous withdata transmitted by the repeaters of the selected repeater group and thedata transmitted by each of the repeaters of the selected repeater groupis transmitted from the start position of the first zone of the frame ineach of the repeaters of the selected repeater group.
 19. The apparatusof claim 18, wherein the BS transmits third data to the MS in the firstzone of the frame in cooperation with the repeaters of the selectedrepeater group.
 20. The apparatus of claim 17, wherein the BS counts thenumber of the repeaters of the selected repeater group, transmits thefirst data directly to the MS when the number of the repeaters of theselected repeater group is 0, transmits the first data to the MS via thesingle repeater of the selected repeater group when the number of therepeaters of the selected repeater group is 1, and transmits the firstdata to the MS via all repeaters of the selected repeater group when thenumber of the repeaters of the selected repeater group is 2 or larger.21. The apparatus of claim 17, wherein the BS selects a repeater groupbased on repeater group information and Channel Quality Information(CQI) about channel qualities between the MS and repeaters connected tothe MS, the repeater group information and the CQI being received fromthe MS.
 22. The apparatus of claim 17, wherein the BS selects a repeatergroup including repeaters with signal strengths measured by the MSlarger than a threshold from among the plurality of repeater groups. 23.The apparatus of claim 17, wherein the BS selects a repeater groupincluding repeaters with minimal mutual interference from among theplurality of repeater groups.
 24. The apparatus of claim 17, wherein theBS receives a repeater list comprises repeaters within a coverage areaof the BS and Channel Quality Information (CQI) of the repeaters withinthe coverage area of the BS from the MS, calculates a capacity of eachrepeater group using the repeater list, and selects a repeater groupwith a largest capacity.
 25. An apparatus for receiving data in acommunication system, the apparatus comprising: a Mobile Station (MS)for receiving first data transmitted by a Base Station (BS) fromrepeaters of a repeater group, wherein the repeater group is selectedfrom among a plurality of repeater groups, for transmission of the firstdata by the BS, the first data is received according to the number ofthe repeaters of the selected repeater group, and the first datareceived from the repeaters of the selected repeater group is differentaccording to the repeaters of the selected repeater group.
 26. Theapparatus of claim 25, wherein MS transmits repeater group selectinginformation to the BS, for use in selecting the repeater group fortransmission of the first data from among the plurality of repeatergroups, and receives the first data from the repeaters of the repeatergroup after the repeater group selecting information is transmitted. 27.The apparatus of claim 26, wherein the MS measures received signal powerof at least one repeater, generates a repeater list including repeatershaving received signal powers larger than a threshold, measures ChannelQuality Information (CQI) about each repeater combination that can beproduced using the repeater list, and transmits the repeater list andthe CQI to the BS.
 28. The apparatus of claim 27, wherein the CQI is atleast one of Carrier-to-Interference and Noise Ratio (CINR),Signal-to-Noise Ratio (SNR), Signal-to-Interference and Noise Ratio(SINR), Carrier-to-Interference Ratio (CIR), and Received SignalStrength (RSS).
 29. The apparatus of claim 25, wherein the MS receivesinformation about a start position of a first zone of a frame from theBS, and receives second data in a second zone of the frame and the firstdata in the first zone of the frame, starting from the start position ofthe first zone indicated by the received information, wherein the seconddata is identical to and simultaneous with data transmitted by therepeaters of the selected repeater group and the first data is receivedfrom the repeaters of the selected repeater group, starting from thestart position of the first zone of the frame.
 30. The apparatus ofclaim 25, wherein the MS receives third data in the first zone of theframe transmitted by the BS in cooperation with the repeaters of theselected repeater group.
 31. The apparatus of claim 25, wherein the MSgenerates a repeater list using all repeaters within a coverage area ofthe BS, generates repeater combinations using the repeater list,measures Channel Quality Information (CQI) about each of the repeatercombinations, and transmits the repeater list and the CQI to the BS. 32.The apparatus of claim 31, wherein the CQI is at least one ofCarrier-to-Interference and Noise Ratio (CINR), Signal-to-Noise Ratio(SNR), Signal-to-Interference and Noise Ratio (SINR),Carrier-to-Interference Ratio (CIR), and Received Signal Strength (RSS).